The present invention relates to low-fat content, butter-flavored liquid spreads which simulate the flavor, texture, mouthfeel, appearance, and stability of commercial liquid margarine. More particularly, the present invention relates to diet products of this type having a reduction in caloric density of from 50 to 95%, and to a process for preparing them.
In our copending U.S. patent application Ser. No. 095,626, filed Nov. 19, 1979, now U.S. Pat. No. 4,279,941, we describe a low-fat, butter-flavored spread which is solid at serving temperatures. That product, which is based on an oil-in-water emulsion, provides a surprisingly good simulation of butter. An emulsifier system comprising both lipophilic and hydrophilic emulsifiers provides stability and helps provide a solid product. We have now discovered that emulsions very similar to the one disclosed herein can be prepared to form a liquid product.
As in the case of solid low-fat spreads, the prior art patents suggest that liquid products be formed of water-in-oil emulsions. These products can be formed with fat contents as low as 60 or 75%. The problem of obtaining stable water-in-oil emulsions in the liquid state is even more critical than in the solid state. For example, U.S. Pat. No. 3,338,720, to Pichel discloses a process for preparing a liquid spread which is stabilized by a minor proportion of hard fat. This is disadvantageous because hard fat increases viscosity and affects mouthfeel.
Water-in-oil emulsions are known to have an adverse effect on flavor impact. This is so pronounced that it is the problem which was dealt with by Moran in U.S. Pat. No. 4,115,598. Therein, flavor impact for a low-fat spread comprising 35 to 65% by weight of a continuous fat phase and a discontinuous aqueous phase is said to be improved by specially formulating the water-in-oil emulsion to destabilize in the mouth to release the water-soluble flavors.
Further representative of the state of the art of liquid spreads is U.S. Pat. No. 3,796,815 to Lincklaen et al. This patent discloses improving the stability of low-fat spreads of the water-in-oil type by incorporating a specific type of phosphatide in the aqueous phase. However this improvement in stability would seem to adversely affect flavor impact.
In forming solid, lowfat spreads, Josefowicz et al indicate in U.S. Pat. No. 3,457,086 that proteins should be substantially eliminated and that special fats and processing conditions must be employed to obtain emulsion stability. While unstable solid emulsions make certain hot foods, such as toast, soggy and unappetizing, unstable liquid emulsions are wholly unpractical.
Among attempts to provide solid low-fat spreads is the approach described by Nijhoff in U.S. Pat. No. 3,418,133. Therein, edible spreads are described wherein a portion of a fat content is replaced by an aqueous solution of carboxymethyl cellulose. In Example 2, a margarine substitute is described which is prepared from a 50/50 mixture of margarine and aqueous solution. This product presumably has a fat content of about 40% (i.e., one half that of margarine); however, the type of emulsion is not identified and the emulsions do not remain stable at room temperature.
U.S. Pat. No. 3,809,764 to Gabby et al. discloses essentially fat-free products which are characterized as "emulsions" of polyglycerol fatty esters with an aqueous hydrophilic colloid. Among the products, are those which are said to simulate margarine yet contain fat contents of less than 5%. These products, while fairly flavorful and fat mimetic, are significantly different in overall flavor, texture, mouthfeel, and appearance from either margarine or butter.
Richardson, in U.S. Pat. No. 4,156,021, also discloses low-fat compositions said to simulate margarine. Example III of this patent employs about 7% corn oil. The emulsions are said to be of the oil-in-water type but contain high levels of cellulose fiber, which adds its characteristic impact on mouthfeel which is significantly different from that of fat.
Other workers have disclosed stable emulsified products containing oil-in-water emulsions, wherein sugars were employed; however, the necessity for sugar made them sweet and clearly distinct from margarine. Among these is U.S. Pat. No. 3,958,033 to Sims et al. Which relates to shelf-stable, clear, liquid emulsions. The sugar was essential in these formulations to supply the desired sweetness, adjust the refractive index of the aqueous phase to improve product clarity, and enhance shelf stability. Similarly, in U.S. Pat. No. 4,146,652, Kahn et al. describe stable oil-in-water emulsions containing high sugar levels to obtain microbiological stability. In U.S. Pat. No. 4,107,343 to Petricca, the sugar was required for sweetness demanded of the whipped products involved. Thus, despite the disclosure by these patents of stable oil-in-water emulsions with fat contents in the 10 to 30% range, and the disclosure by Sims et al. in Example XXII of a maple-flavored spread, and a confectionary butter cream in Example I of Kahn et al., there is no solution afforded the skilled worker in the art seeking a product which can successfully reproduce the flavor, texture, mouthfeel, stability and appearance of liquid margarine at a caloric density of 5-45 calories per 14 gram serving.